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It is well documented, as reviewed by Labuschagne et al. (2012), that Huntington’s disease (HD) patients often have difficulty recognizing facial cues and understanding emotions of other individuals1, especially regarding the emotion of disgust2. Such emotional deficits can greatly diminish their ability to communicate, which may result in aggravated tension and stress between patients and caregivers.

In order to understand the potential spectrum of emotional recognition deficits in HD and its relationship to certain medications, a recent study conducted as part of a multi-site international project (TRACK-HD) examined emotion recognition in relation to the use of neuroleptic and selective serotoninreuptake inhibitor (SSRI) medications1.

Neuroleptic drugs are anti-psychotic medications that affect one’s cognition and behavior. These drugs have the potential to cause apathy, reduced range of emotion, confusion and agitation3. Physicians prescribe HD patients neuroleptics in order to treat chorea and behavioral disturbances such as irritability and anger outbursts, and less often for psychotic symptoms1.

SSRIs are anti-depressant medications, which, on top of being used for depression treatment, may also be used to subdue behavioral issues such as irritability and aggression3.

In clinical trials focusing on diseases other than HD, these medications have been found to reduce emotional capabilities and cause symptoms such as affective indifference, emotional blunting, reduced facial expressiveness, and reduced intensity and frequency of emotional experiences1. The aim of this study was to determine if these observations are applicable to the HD patients.

The researchers identified 344 participants that ranged from premanifest patients (individuals which have already been diagnosed as carriers of the HD mutation, but have yet to start displaying any signs of HD-related symptoms ; n=115), early HD patients (n=113), and controls (n=116). The participants were between 18 and 65 years of age with no history of other neurological illnesses. Using six emotional expressions and a neutral expression, the researchers examined how these three different groups would identify and respond to the emotions demonstrated. Additionally, the researchers focused on the subset of early HD patients who were taking neuroleptic or SSRI medications in order to compare the emotion recognition performance with that of early HD patients who were not taking these medications.

In order to gage emotional recognition, the researchers utilized a computer tablet to show facial stimuli from the Ekman and Friesen face stimulus set5. Each experimental trial included a single face showing one emotional expression (anger, disgust, fear, happiness, sadness, or surprise) or a neutral expression. Subsequently, participants were advised to press one of the seven emotional word response labels displayed below the facial stimuli, allowing them ample time to signify the emotion of the face. Each participant performed 70 experimental trials.

Overall, symptomatic participants were significantly impaired when it came to recognizing the following individual emotions: anger, fear, and surprise. This impairment is greater than that observed in the unaffected controls and the premanifest groups. Those in the early stage of HD who were taking the neuroleptics were significantly less accurate at recognizing the emotions of fear, happiness and sadness than the unmedicated group. However, members of the early HD group who were taking SSRI medication had results that correlated with improved facial recognition, particularly for disgust and sadness emotions.

This study showed that neuroleptic use by HD patients was associated with worse facial emotion recognition, whereas SSRI use was associated with better emotion recognition. These findings are of high significance for HD patient care since medications commonly prescribed to patients may difficult communication and affect social interactions. HD patients are more susceptible to misinterpret neutral events that are actually irrelevant as something that is significant, leading to issues such as depression. Prescribing medication-targeting symptoms such as depression seems to further alter the ability of those affected to communicate or read emotional cues from those around them. Therefore, a better understanding of the effects of neuroleptics and SSRIs is of great importance.